The Mariners approached the offseason with a modest agenda. But even with the bar of expectations set low, their moves were uninspiring. They invested $7.5 million in a two-year deal for Olivo, who brings energy, some home run pop and a career .283 on-base percentage to the lineup. That’s the lowest of any active player with at least 3,000 plate appearances. And Cust, the new DH, homered once every 26.8 at bats last season, compared to a homer every 14.6 ABs in 2008.